Hunting the Shmoo

Screencasts and blog posts on workflow, productivity, tools, Mozilla and whatever else tickles my fancy.

Taskgraph Like a Pro

Have you ever needed to inspect the taskgraph locally? Did you have a bad time? Learn how to inspect the taskgraph like a PRO. For the impatient skip to the installation instructions below.


First you’ll need to install fzf, if you’ve used mach try fuzzy before, it’s already on your system under ~/.mozbuild/fzf, just make sure it’s on your $PATH.

Next install fx:

$ npm install fx

Finally, add the following shell function to your ~/.bashrc or equivalent:

tf () {
	fx "tg => String(require(\"child_process\").spawnSync(\"fzf\", [\"-f\", \"$1\"], {\"input\": Object.keys(tg).join(\"\n\")}).output).split(\"\n\").reduce((obj, key) => { obj[key] = tg[key]; return obj; }, {})" | fx

That’s it!


Simply pipe the output of mach taskgraph full -J into the tf function (preferably saving it to a file first:

$ ./mach taskgraph full -J > full.taskgraph
$ cat full.taskgraph | tf "win64 mochitest | reftest -1$"

The above will filter down all chunk 1 mochitest and reftest tasks on win64. The query syntax is identical to the one used with mach try fuzzy. See man fzf for more details.

Happy inspecting!